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Moyamoya disease and syndrome an unusal cause of stroke
1. An unusual cause of stroke
DR. SURENDRS GODARA
SENIOUR RESIDENT
DEPT.OF PEADIATRICS
Unit II
CNBC DELHI
2. Acute stroke syndrome
• Common cause of acute hemiplegia in
children
• Incidence- 2-3/100,000 per year
• Cause of stroke is established in 75% of cases
• “The acute onset of a focal neurologic deficit
in a child is stroke until proven otherwise.”
Nelson text book of pediatrics,19th edition
4. Clinical presentation of stroke
• Most common presentation is focal neurologic
deficit
• Most common focal presentation is
hemiparesis
• May present with visual, speech, sensory or
balance deficit
5. Risk factors for arterial ischemic stoke
in children
• Arteriopathic
– Focal cerebral arteriopathy (FCA)
– Post varicella angiopathy (PVA)
– Transient cerebral arteriopathy (TCA)
– Childhood primary angitis of childhood (cPACNS)
– Systemic/secondary vasculitis(Takayasu arteritis)
– Moyamoya disease
– Craniocervical arterial dissection
– arterial infection (bacterial/tubercular meningitis)
8. WORK UP FOR STROKE
-
CBC
ESR (vasculitis)
CSF analysis(meningitis)
Blood culture(infective endocarditis)
Tests for sickling-sodium metabisulphite test
CRP,C3,C4,ANA,RF (vasculitis and connective
tissue disorder)
9. • Lupus anticoagulant( SLE)
• PT, aPTT (coagulation disorder)
• Protein C and S,antithrombin
3, lipoprotein(a), factor V leiden(procoagulant
states)
• Anticardiolipin antibodies( for antiphospholipid
syndrome)
• Serum homocysteine levels and urine for
homocystinuria
• Lipid profile
• Serum lactate/pyruvate( MELAS)
11. Management
• The issues of treatment of ischemic stroke involve
both initial treatment of the acute stroke event to
preserve neurological function and long-term
efforts to prevent a second stroke, which occurs
in 10% to25% of children with stroke.
• Supportive measures should include control of
fever, maintenance of normal oxygenation,
control of systemic hypertension, and
normalization of serum glucose levels ,treat
dehydration and anemia
12. Medications for the Secondary Prevention of
Ischemic Stroke in Children
1. Anticoagulation with LMWH is useful for long-term anticoagulation of children
with a substantial risk of recurrent cardiac embolism, CVST, and selected
hypercoagulable states
2 Anticoagulation with warfarin is reasonable for the long-term anticoagulation
of children with a substantial risk of recurrent cardiac
embolism, CCAD, CVST, or selected hypercoagulable states
3 Aspirin is a reasonable option for the secondary prevention of AIS in children
whose infarction is not due to SCD and in children who are not known to have a
high risk of recurrent embolism or a severe hypercoagulable disorder
A dose of 3 to 5 mg/kg per day is a reasonable initial aspirin dose for stroke
prevention in children .
4 Thrombolytic therapy with tPA may be considered inselected children with
CVST
13. Moyamoya Disease-Review
• Takaku, Suzuki and others described moyamoya disease in
Japan in the sixties
• Moyamoya disease is a cerebrovascular disease characterized
by slowly progressive steno-occlusive changes in the terminal
portions of the bilateral internal carotid arteries (ICA) and
their main branches, which results in the formation of a fine
vascular network at the base of the brain (moyamoya vessels)
to compensate for the steno-occlusion .
• The hazy appearance of these hypertrophied collaterals on
angiography resembles a puff of smoke (moyamoya in
Japanese); thus, Suzuki and Takaku named this novel disorder
“moyamoya disease” .
14. Definitions and diagnosis
• definite moyamoya disease is diagnosed when conventional
angiography shows the following findings:
• stenosis or occlusion in the terminal ICA
and/or
proximal portion of anterior cerebral artery (ACA)
and/or
middle cerebral artery (MCA)
• abnormal vascular networks (moyamoya vessels) in the basal
ganglia; and bilateral lesions.
15. • Patients with unilateral lesions are diagnosed
as having probable moyamoya disease.
• When an underlying cause is found, such as
Down syndrome, neurofibromatosis type 1,
sickle cell disease, and radiation therapy, a
diagnosis of moyamoya syndrome is given
16. Etiology
• Etiology of the disease is still unknown.
• A genetic mode of inheritance is considered
possible because of the higher incidence of the
disease in Japan and Korea
• There have been recent reports of increased
familial incidence of the disease.
• This apparent increase may partly reflect the
fact that wide spread use of magnetic
resonance imaging (MRI) and magnetic
resonance angiography have been detecting
the disease in asymptomatic patients.
17. • In a recent total genome search, a linkage was
found between the disease and markers
located at 3p24.2-26.
• Another linkage study using markers on
chromosome 6, where the HLA gene is
located, showed a possible linkage of the
marker D6S441 to the disease.
• DNA typing of HLA also indicates that the
disease is probably genetic in origin.
• There have also been reports of linkage to
chromosome 17.
18. Factors involved in pathogenesis
• Fibroblast growth factor There is some
evidence to show that CSF bFGF may play a
role in the pathogenesis of the disease.
• Transforming growth beta factor 1 (TGF beta
1), a factor involved in angiogenesis and
expression of connective tissue genes.
• An unknown CSF protein
• The role of prostaglandin studies have shown
that the arterial smooth muscle cells in
moyamoya activate cox2 in response to
inflammation, and produce excess pgs which
may promote intimal thickening.
19. • A possible role for infection in the
pathogenesis has been proposed. The
evidence is still inconclusive but some studies
have suggested a relationship with EpsteinBarr virus infection. This was based on the
increased presence of EBV DNA and antibody
in patients with moyamoya
20. EPIDEMIOLOGY
• The incidence of moyamoya disease is high in countries in east Asia, such
as Japan and Korea.
• In Japan,the annual prevalence and incidence have been estimated to be
3.16–10.5 and 0.35–0.94 per 100,000 .
• The annual incidences in the USA and Europe have been reported to be
about 10% of that in Japan .
• incidence in india is unknown.
• The female to male ratio has been shown to be 1.8–2.2(female
predominance) .
• A bimodal age distribution i.e5 years 40 years .
• The incidence of familial occurrence is high, as 15%
• The female to male ratio in familial moyamoya disease is 5.0
21.
22. HISTOPATHLOGY
• The histopathological findings for the carotid terminations
include fibrocellular thickening of the intima, irregular
undulation of the internal elastic lamina, and attenuation of
the media .
• Moyamoya vessels have fibrin deposits in their
walls, fragmented elastic laminae,attenuated media, and
microaneurysms.
• Collapse of the arterial lumen and subsequent thrombosis
can be seen in moyamoya vessels , which might be closely
associated with the onset of ischemic stroke and hemorrhage
23. Clinical features
• Moyamoya disease has the highest incidence during the first decade of life.
• Children present most frequently with transient ischemic attacks or
ischemic strokes.
• Typical symptoms are monoparesis, hemiparesis, aphasia, and dysarthria.
Headache, seizures, and involuntary movements, such as hemichorea,can
be serious symptoms associated with pediatric moyamoya disease.
•
slowly progressive mental impairment has also been obeserved
• Motor disturbances are the most common 80.5%
• Convulsions occur in about 9%.
24. Clinical features cont…
•
Episodic symptoms are often precipitated by hyperventilation or rise in body
temperature
•
Endocrine dysfunction : There have been a few case reports of hypothalamicpituitary dysfunction associated with moyamoya. Patients have presented with
evidence of pituitary and thyroid hypofunction. It has been suggested that children
with moyamoya be closely monitored for hypothalamic-pituitary dysfunction.
•
Hemorrhagic type moyamoya disease : Intracranial hemorrhage is more common in
adults with the disease but can manifest in children. Factors, which may contribute
to bleeding include hypertension and aneurysms.
25. Angiographic features of moyamoya
• There is narrowing and occlusion of the supraclinoid portions of the internal
carotid artery and the proximal portions of the anterior and middle cerebral
artery
• The formation of network of vessels at the frontal base with blood supply
from the branches of the ophthalmic artery is known as ethmoidal
moyamoya.
• Dilatation of the basilar artery and formation of moyamoya network by
perforating branches of the posterior cerebral artery is known as posterior
basal moyamoya.
• Vault moyamoya is due to development of extra and intracranial transdural
leptomeningeal collaterals between pial vessel and branches of the external
carotid artery.
26. Angiographic staging of
moyamoya disease
• Stage I - Narrowing of terminal ICA
• Stage II - Initiation of moyamoya vessels
(dilatation of intracerebral arteries)
• Stage III - Intensification of moyamoya vessels,defection of the
ACA and MCA is observed.
• Stage IV -Minimization of moyamoya vessels, defection of PCA
• Stage V -further Reduction of moyamoya, disappearance of
major cerebral arteries.
• Stage VI- Disappearance of moyamoya collaterals,cerebral
blood supply is only from external carotid arteries.
27. • A novel grading system for MRA in moyamoya
disease has been proposed , based on the
severity of the occlusive changes of the
ICA, ACA, MCA,and PCA, and the visibility of their
distal branches.MRA scores correlate well with
the six-stages of cerebral angiography with high
sensitivity and specificity. MRA grade 1 correlates
with angiography stages 1 and 2, and MRA grades
2, 3, and 4 with angiography stages 3 (mainly), 4
(mainly), and 5 to 6, respectively.
28. Imaging
• Computed tomography
may be useful for detetecting hemorrhage. Low density areas may suggest
infarction. There may be evidence of cerebral atrophy. Grey and white
matter of the frontal lobe is most frequently affected.
• Electroencephalographic changes
EEG changes reported in moyamoya include posterior
slowing and centrotemporal slow activity. There is sleep spindle depression.
EEG has sometimes been used in the past for screening but has generally
been replaced by magnetic resonance imaging. . Although the re-build up on
EEG (reappearance of slow waves after the end of hyperventilation) is
pathognomonic for moyamoya disease, hyperventilation during EEG
examination should be avoided when a diagnosis of moyamoya disease is
suspected or given, because it can induce iatrogenic TIA or infarction.
29. Magnetic resonance imaging
• It has been used extensively in Japan for screening purposes.
• Moyamoya vessels are visualized as multiple small round or
tortuous low intensity areas extending from the suprasellar
cisterns to the basal ganglia.
• Occlusive changes in the distal internal carotid, anterior
cerebral artery and middle cerebral artery and ischemic
cerebral lesions and collaterals can also be visualized.
30. • Proton magnetic resonance spectroscopy (MRS) is an effective
method to noninvasively investigate cerebral metabolism.
• T1- and T2-weighted images are also useful for identifying
ischemic lesions and moyamoya vessels as multiple flow voids
in these regions
• fluid-attenuated inversion recovery (FLAIR) images are useful
for showing chronic infarctions .
• Diffusion-weighted images (DWI) can show the acute stage of
ischemia.
31. ANGIOGRAPHY
• Cerebral angiography is still the gold standard, however,it is
not mandatory for the diagnosis of moyamoya disease when
MRI and MRA show typical findings
• As the cerebral angiography is invasive and not easy to
perform, pediatric neurologists have to be familiar with the
findings of moyamoya disease on MRI and MRA, which can be
performed in a non-invasive manner.
32.
33. MRA of the same patient (a) and a normal control (b). MRA shows stenosis or occlusion in the terminal
ICA, proximal ACA and MCA
(arrows), and moyamoya vessels in the basal ganglia (bold arrows
34. Treatment
• MEDICAL
• Medical treatment with vasodilators, corticosteroids, antiplatelet agents etc.
has been tried with doubtful efficacy.
• Patients are often put on aspirin, even though there is no evidence that it
stops or reverses arterial occlusion.
35. SURGERY
• INDICATION
Indications for surgical treatment of moyamoya disease include a
combination of patients' symptoms and radiographic evaluation.
• Many moyamoya patients are candidates for procedures to augment
blood flow if they have symptoms related to ischemia or previous
hemorrhage.
• Progressive neurologic deficits, such as cognitive decline or progressive
seizures also are indications for bypass.
36. OPERATIVE TECHNIQUE
•
DIRECT revascularization methods
STA-MCA Bypass
•
INDIRECT revascularization methods
Encephaloduroarteriomyosynangiosis(EDAS)
Encephalomyosynangiosis (EMS).
Omental Transposition.
•
•
OUTCOME
Surgical treatment of moyamoya disease using various revascularization techniques has
been shown to be safe and effective in reducing ischemic events, in both adults and
children. Clinically, revascularization in moyamoya patients has shown to be beneficial
in reducing transient ischemic attacks, and, although the evidence is less conclusive,
some studies suggest benefit for reducing hemorrhagic events. Post-revascularization
angiography and MRI studies often reveal a reduction in moyamoya vessels that closely
parallels improvement in symptoms. Additionally, reports in the literature that
revascularization techniques result in improvement of cerebral blood flow studies, in
both adult and pediatric moyamoya patients, are increasing in number.
37. Conclusion
• Moyamoya disease is an important cause of cerebral stroke in
children, especially in east Asian countries.
•
For the pediatric neurologist, it is important to be familiar with the clinical
manifestations and MRI/MRA findings in moyamoya disease or syndrome
to make an early diagnosis leading to a good prognosis.
• Genetic analysis of familial moyamoya disease might help to determine
the pathogenesis in the near future.
38. References
• Moyamoya disease: a review.
Gosalakkal JA Neurol India. 2002 Mar;50(1):6-10.
• Review article Moyamoya disease in childrenJun-ichi
Takanashi Department of Pediatrics, Kameda Medical
Center, Kamogawa-shi, Japan
• Surgical Management of Moyamoya Disease Steven
D. Chang, M.D., and Gary K.
Steinberg, M.D., Ph.D.Department of Neurosurgery
and the Stanford Stroke Center, Stanford University
Medical Center, Stanford,California, U.S.A
